This study seeks to develop and characterize a mutagenic test system in the frog, Rana pipiens, and to compare the results obtained with results from other mutagenic test systems. The test system will consist of administration of mutagenic chemicals to male frogs, recovery of the treated animals' sperm, fertilization of eggs with the sperm, and analysis of the developing embryos for mutagenic changes. A dose response relationship will be established for both chromosome aberrations and abnormal morphology of developing embryos for the known mutagen, triethylenemelamine (TEM), we will compare somatic versus gametic chromosomal changes within the same animal, and we will confirm the genetic nature of induced changes by amphibian nuclear transplantation (cloning). The usefulness for mutagenesis screening of androgenetic haploid embryos will be studied. The effects on frogs of different routes of administration of test chemicals will be tested. The mutagenic protential of varying classes of known chemical mutagens will be studied.